Elementary, simple, fundamental, merely functional.
Of or pertaining to a base; having a pH greater than 7.
Unremarkable or uninteresting; boring; uncool.
Necessary, essential for life or some process.
An elementary building block, e.g. a fundamental piece of knowledge.
A necessary commodity, a staple requirement.
Basic training.
Pertaining to, derived from, or perceived by, intuition; intuitive.